diff --git a/minix/include/env.h b/minix/include/env.h
index 7f9c6fd75..2f60f42f0 100644
--- a/minix/include/env.h
+++ b/minix/include/env.h
@@ -1,4 +1,4 @@
 int env_parse(const char *env, const char *fmt, int field, long *param, long min,
 	long max);
-void env_panic(const char *env);
+void __dead env_panic(const char *env);
 int env_prefix(char *env, char *prefix);
diff --git a/minix/include/minix/sef.h b/minix/include/minix/sef.h
index 25434410d..6fb69fad9 100644
--- a/minix/include/minix/sef.h
+++ b/minix/include/minix/sef.h
@@ -10,7 +10,7 @@ void sef_startup(void);
 int sef_receive_status(endpoint_t src, message *m_ptr, int *status_ptr);
 endpoint_t sef_self(void);
 void sef_cancel(void);
-void sef_exit(int status);
+void __dead sef_exit(int status);
 #define sef_receive(src, m_ptr) sef_receive_status(src, m_ptr, NULL)
 
 /* SEF Debug. */
diff --git a/minix/lib/libsys/Makefile b/minix/lib/libsys/Makefile
index 39535b912..a73c58c89 100644
--- a/minix/lib/libsys/Makefile
+++ b/minix/lib/libsys/Makefile
@@ -1,9 +1,8 @@
-NOGCCERROR=yes
-NOCLANGERROR=yes
-
 # Makefile for libsys
 .include <bsd.own.mk>
 
+NOGCCERROR=yes
+
 CPPFLAGS+= -D_MINIX_SYSTEM -D_SYSTEM
 
 LIB=		sys
diff --git a/minix/lib/libsys/arch/i386/Makefile.inc b/minix/lib/libsys/arch/i386/Makefile.inc
index e35b04bd5..9b9aa2d38 100644
--- a/minix/lib/libsys/arch/i386/Makefile.inc
+++ b/minix/lib/libsys/arch/i386/Makefile.inc
@@ -22,7 +22,6 @@ SRCS+=  \
         sys_voutb.c \
         sys_voutl.c \
         sys_voutw.c \
-        timing.c \
         tsc_util.c \
         vbox.c
 
diff --git a/minix/lib/libsys/arch/i386/sys_readbios.c b/minix/lib/libsys/arch/i386/sys_readbios.c
index 497f3c4bf..49350acec 100644
--- a/minix/lib/libsys/arch/i386/sys_readbios.c
+++ b/minix/lib/libsys/arch/i386/sys_readbios.c
@@ -10,6 +10,6 @@ size_t size;			/* Amount of data to read */
 
   m.m_lsys_krn_readbios.size = size;
   m.m_lsys_krn_readbios.addr = address;
-  m.m_lsys_krn_readbios.buf = buf;
+  m.m_lsys_krn_readbios.buf = (vir_bytes)buf;
   return(_kernel_call(SYS_READBIOS, &m));
 }
diff --git a/minix/lib/libsys/arch/i386/sys_sdevio.c b/minix/lib/libsys/arch/i386/sys_sdevio.c
index 8516fb8dd..c589f63f5 100644
--- a/minix/lib/libsys/arch/i386/sys_sdevio.c
+++ b/minix/lib/libsys/arch/i386/sys_sdevio.c
@@ -16,7 +16,7 @@ vir_bytes offset;			/* offset from grant */
     m_io.m_lsys_krn_sys_sdevio.request = req;
     m_io.m_lsys_krn_sys_sdevio.port = port;
     m_io.m_lsys_krn_sys_sdevio.vec_endpt = proc_nr;
-    m_io.m_lsys_krn_sys_sdevio.vec_addr = buffer;
+    m_io.m_lsys_krn_sys_sdevio.vec_addr = (vir_bytes)buffer;
     m_io.m_lsys_krn_sys_sdevio.vec_size = count;
     m_io.m_lsys_krn_sys_sdevio.offset = offset;
 
diff --git a/minix/lib/libsys/arch/i386/timing.c b/minix/lib/libsys/arch/i386/timing.c
deleted file mode 100644
index 51acc7b08..000000000
--- a/minix/lib/libsys/arch/i386/timing.c
+++ /dev/null
@@ -1,83 +0,0 @@
-
-#include <minix/sysutil.h>
-#include <minix/syslib.h>
-#include <minix/config.h>
-#include <minix/const.h>
-#include <minix/minlib.h>
-
-#define HIGHCOUNT	0
-#define LOWCOUNT	1
-
-#define START		0
-#define END		1
-
-void util_timer_start(util_timingdata_t *timingdata, char *name)
-{
-	size_t i;
-
-	if(timingdata->names[0] == '\0') {
-		for(i = 0; i < sizeof(timingdata->names) && *name; i++)
-			timingdata->names[i] = *name++;
-		timingdata->names[sizeof(timingdata->names)-1] = '\0';
-	}
-
-	if (timingdata->starttimes[HIGHCOUNT]) {
-		panic("restart timer?");
-		return;
-	}
-
-	read_tsc((u32_t *) &timingdata->starttimes[HIGHCOUNT],
-		 (u32_t *) &timingdata->starttimes[LOWCOUNT]);
-}
-
-void util_timer_end(util_timingdata_t *timingdata)
-{
-	unsigned long h, l, d = 0;
-	int bin;
-
-	read_tsc((u32_t *) &h, (u32_t *) &l);
-	if (!timingdata->starttimes[HIGHCOUNT]) {
-		panic("timer stopped but not started");
-		return;
-	}
-	if (timingdata->starttimes[HIGHCOUNT] == h) {
-		d = (l - timingdata->starttimes[LOWCOUNT]);
-	} else if (timingdata->starttimes[HIGHCOUNT] == h-1 &&
-		timingdata->starttimes[LOWCOUNT] > l) {
-		d = ((ULONG_MAX - timingdata->starttimes[LOWCOUNT]) + l);
-	} else {
-		timingdata->misses++;
-		return;
-	}
-	timingdata->starttimes[HIGHCOUNT] = 0;
-	if (!timingdata->lock_timings_range[START] ||
-		d < timingdata->lock_timings_range[START] ||
-		d > timingdata->lock_timings_range[END]) {
-		int t;
-		if (!timingdata->lock_timings_range[START] ||
-			d < timingdata->lock_timings_range[START])
-			timingdata->lock_timings_range[START] = d;
-		if (!timingdata->lock_timings_range[END] ||
-			d > timingdata->lock_timings_range[END])
-			timingdata->lock_timings_range[END] = d;
-		for(t = 0; t < TIMING_POINTS; t++)
-			timingdata->lock_timings[t] = 0;
-		timingdata->binsize =
-		 (timingdata->lock_timings_range[END] -
-		 timingdata->lock_timings_range[START])/(TIMING_POINTS+1);
-		if (timingdata->binsize < 1)
-		  timingdata->binsize = 1;
-		timingdata->resets++;
-	}
-	bin = (d-timingdata->lock_timings_range[START]) /
-		timingdata->binsize;
-	if (bin < 0 || bin >= TIMING_POINTS) {
-		/* not serious, but can't happen, so shouldn't */
-		panic("bin out of range: %d", bin);
-	} else {
-		timingdata->lock_timings[bin]++;
-		timingdata->measurements++;
-	}
-
-	return;
-}
diff --git a/minix/lib/libsys/env_get_prm.c b/minix/lib/libsys/env_get_prm.c
index 590c6888a..de6d556b1 100644
--- a/minix/lib/libsys/env_get_prm.c
+++ b/minix/lib/libsys/env_get_prm.c
@@ -50,7 +50,7 @@ int env_get_param(const char *key, char *value, int max_len)
   m.m_lsys_krn_sys_getinfo.request = GET_MONPARAMS;
   m.m_lsys_krn_sys_getinfo.endpt = SELF;
   m.m_lsys_krn_sys_getinfo.val_len = sizeof(mon_params);
-  m.m_lsys_krn_sys_getinfo.val_ptr = mon_params;
+  m.m_lsys_krn_sys_getinfo.val_ptr = (vir_bytes)mon_params;
   if ((s=_kernel_call(SYS_GETINFO, &m)) != OK) {
 	printf("SYS_GETINFO: %d (size %u)\n", s, sizeof(mon_params));
 	return(s);
diff --git a/minix/lib/libsys/env_panic.c b/minix/lib/libsys/env_panic.c
index 4ca0dcd42..6e0c9357f 100644
--- a/minix/lib/libsys/env_panic.c
+++ b/minix/lib/libsys/env_panic.c
@@ -1,5 +1,6 @@
 #include "sysutil.h"
 #include <string.h>
+#include <env.h>
 
 /*=========================================================================*
  *				env_panic				   *
diff --git a/minix/lib/libsys/getsysinfo.c b/minix/lib/libsys/getsysinfo.c
index 7154b5852..8bdc1ec26 100644
--- a/minix/lib/libsys/getsysinfo.c
+++ b/minix/lib/libsys/getsysinfo.c
@@ -26,7 +26,7 @@ int getsysinfo(
 
   memset(&m, 0, sizeof(m));
   m.m_lsys_getsysinfo.what = what;
-  m.m_lsys_getsysinfo.where = where;
+  m.m_lsys_getsysinfo.where = (vir_bytes)where;
   m.m_lsys_getsysinfo.size = size;
   return _taskcall(who, call_nr, &m);
 }
diff --git a/minix/lib/libsys/sched_start.c b/minix/lib/libsys/sched_start.c
index 1cd2e510e..6cce480f4 100644
--- a/minix/lib/libsys/sched_start.c
+++ b/minix/lib/libsys/sched_start.c
@@ -2,13 +2,9 @@
 #include <assert.h>
 #include <machine/archtypes.h>
 #include <minix/timers.h>
+#include <minix/sched.h>
 #include <string.h>
 
-#include "kernel/config.h"
-#include "kernel/const.h"
-#include "kernel/type.h"
-#include "kernel/proc.h"
-
 /*===========================================================================*
  *				sched_inherit				     *
  *===========================================================================*/
diff --git a/minix/lib/libsys/sched_stop.c b/minix/lib/libsys/sched_stop.c
index 889a03bcc..d6ad73cdc 100644
--- a/minix/lib/libsys/sched_stop.c
+++ b/minix/lib/libsys/sched_stop.c
@@ -1,6 +1,7 @@
 #include "syslib.h"
 #include <assert.h>
 #include <string.h>
+#include <minix/sched.h>
 
 /*===========================================================================*
  *				sched_stop				     *
diff --git a/minix/lib/libsys/sef.c b/minix/lib/libsys/sef.c
index 389118719..c9bdd49d8 100644
--- a/minix/lib/libsys/sef.c
+++ b/minix/lib/libsys/sef.c
@@ -17,6 +17,7 @@ int sef_self_receiving;
 /* Debug. */
 #if SEF_INIT_DEBUG || SEF_LU_DEBUG || SEF_PING_DEBUG || SEF_SIGNAL_DEBUG
 #define SEF_DEBUG_HEADER_MAXLEN 32
+static int sef_debug_init = 0;
 static time_t sef_debug_boottime = 0;
 static u32_t sef_debug_system_hz = 0;
 static time_t sef_debug_time_sec = 0;
@@ -239,7 +240,6 @@ void sef_exit(int status)
 /* System services use a special version of exit() that generates a
  * self-termination signal.
  */
-  message m;
 
   /* Ask the kernel to exit. */
   sys_exit();
@@ -262,40 +262,26 @@ static void sef_debug_refresh_params(void)
 {
 /* Refresh SEF debug params. */
   clock_t uptime;
-  int r;
 
-  /* Get boottime the first time. */
-  if(!sef_debug_boottime) {
-      r = sys_times(NONE, NULL, NULL, NULL, &sef_debug_boottime);
-      if ( r != OK) {
-          sef_debug_boottime = -1;
-      }
-  }
-
-  /* Get system hz the first time. */
-  if(!sef_debug_system_hz) {
-      r = sys_getinfo(GET_HZ, &sef_debug_system_hz,
-          sizeof(sef_debug_system_hz), 0, 0);
-      if ( r != OK) {
-          sef_debug_system_hz = -1;
-      }
+  /* Get boottime and system hz the first time. */
+  if(!sef_debug_init) {
+      if (sys_times(NONE, NULL, NULL, NULL, &sef_debug_boottime) != OK)
+	  sef_debug_init = -1;
+      else if (sys_getinfo(GET_HZ, &sef_debug_system_hz,
+        sizeof(sef_debug_system_hz), 0, 0) != OK)
+	  sef_debug_init = -1;
+      else
+	  sef_debug_init = 1;
   }
 
   /* Get uptime. */
   uptime = -1;
-  if(sef_debug_boottime!=-1 && sef_debug_system_hz!=-1) {
-      r = sys_times(NONE, NULL, NULL, &uptime, NULL);
-      if ( r != OK) {
-            uptime = -1;
-      }
-  }
-
-  /* Compute current time. */
-  if(sef_debug_boottime==-1 || sef_debug_system_hz==-1 || uptime==-1) {
+  if (sef_debug_init < 1 || sys_times(NONE, NULL, NULL, &uptime, NULL) != OK) {
       sef_debug_time_sec = 0;
       sef_debug_time_us = 0;
   }
   else {
+      /* Compute current time. */
       sef_debug_time_sec = (time_t) (sef_debug_boottime
           + (uptime/sef_debug_system_hz));
       sef_debug_time_us = (uptime%sef_debug_system_hz)
diff --git a/minix/lib/libsys/sef_fi.c b/minix/lib/libsys/sef_fi.c
index 36ae8d6f1..9f5265969 100644
--- a/minix/lib/libsys/sef_fi.c
+++ b/minix/lib/libsys/sef_fi.c
@@ -5,6 +5,8 @@
 
 EXTERN __attribute__((weak)) int edfi_ctl_process_request(void *ctl_request);
 
+EXTERN int do_sef_fi_request(message *m_ptr);
+
 /*===========================================================================*
  *                            do_sef_fi_request             		     *
  *===========================================================================*/
diff --git a/minix/lib/libsys/stacktrace.c b/minix/lib/libsys/stacktrace.c
index 8185956a9..d7e87eb9c 100644
--- a/minix/lib/libsys/stacktrace.c
+++ b/minix/lib/libsys/stacktrace.c
@@ -8,6 +8,7 @@ Copyright 1995 Philip Homburg
 
 #include <stdio.h>
 #include <string.h>
+#include <minix/sysutil.h>
 
 typedef unsigned int reg_t;
 
diff --git a/minix/lib/libsys/sys_getinfo.c b/minix/lib/libsys/sys_getinfo.c
index a9a463d1e..1b1076bdf 100644
--- a/minix/lib/libsys/sys_getinfo.c
+++ b/minix/lib/libsys/sys_getinfo.c
@@ -17,9 +17,9 @@ int len2;				/* length or process nr */
 
     m.m_lsys_krn_sys_getinfo.request = request;
     m.m_lsys_krn_sys_getinfo.endpt = SELF;	/* always store values at caller */
-    m.m_lsys_krn_sys_getinfo.val_ptr = ptr;
+    m.m_lsys_krn_sys_getinfo.val_ptr = (vir_bytes)ptr;
     m.m_lsys_krn_sys_getinfo.val_len = len;
-    m.m_lsys_krn_sys_getinfo.val_ptr2 = ptr2;
+    m.m_lsys_krn_sys_getinfo.val_ptr2 = (vir_bytes)ptr2;
     m.m_lsys_krn_sys_getinfo.val_len2_e = len2;
 
     return(_kernel_call(SYS_GETINFO, &m));
diff --git a/minix/lib/libsys/sys_safecopy.c b/minix/lib/libsys/sys_safecopy.c
index 2db46f9a8..1b097b24d 100644
--- a/minix/lib/libsys/sys_safecopy.c
+++ b/minix/lib/libsys/sys_safecopy.c
@@ -16,7 +16,7 @@ int sys_safecopyfrom(endpoint_t src_e,
   copy_mess.m_lsys_kern_safecopy.from_to = src_e;
   copy_mess.m_lsys_kern_safecopy.gid = gr_id;
   copy_mess.m_lsys_kern_safecopy.offset = offset;
-  copy_mess.m_lsys_kern_safecopy.address = address;
+  copy_mess.m_lsys_kern_safecopy.address = (void *)address;
   copy_mess.m_lsys_kern_safecopy.bytes = bytes;
 
   return(_kernel_call(SYS_SAFECOPYFROM, &copy_mess));
@@ -36,7 +36,7 @@ int sys_safecopyto(endpoint_t dst_e,
   copy_mess.m_lsys_kern_safecopy.from_to = dst_e;
   copy_mess.m_lsys_kern_safecopy.gid = gr_id;
   copy_mess.m_lsys_kern_safecopy.offset = offset;
-  copy_mess.m_lsys_kern_safecopy.address = address;
+  copy_mess.m_lsys_kern_safecopy.address = (void *)address;
   copy_mess.m_lsys_kern_safecopy.bytes = bytes;
 
   return(_kernel_call(SYS_SAFECOPYTO, &copy_mess));
diff --git a/minix/lib/libsys/sys_vircopy.c b/minix/lib/libsys/sys_vircopy.c
index 28492950a..4ee5033ad 100644
--- a/minix/lib/libsys/sys_vircopy.c
+++ b/minix/lib/libsys/sys_vircopy.c
@@ -1,4 +1,5 @@
 #include "syslib.h"
+#include <string.h>
 
 int sys_vircopy(src_proc, src_vir, 
 	dst_proc, dst_vir, bytes, flags)
diff --git a/minix/lib/libsys/sysutil.h b/minix/lib/libsys/sysutil.h
index 497f755f9..88be29f59 100644
--- a/minix/lib/libsys/sysutil.h
+++ b/minix/lib/libsys/sysutil.h
@@ -1,7 +1,5 @@
 /*	sysutil.h - System library utilities.	*/
 
-#define _SYSTEM
-
 #include <lib.h>		/* common to all libraries */
 #include <minix/com.h>		/* need task numbers + message types */
 #include <minix/syslib.h>	/* need ipc_sendrec, _taskcall, etc */
diff --git a/minix/lib/libsys/vm_cache.c b/minix/lib/libsys/vm_cache.c
index 75a193be7..c94c1e2f8 100644
--- a/minix/lib/libsys/vm_cache.c
+++ b/minix/lib/libsys/vm_cache.c
@@ -12,8 +12,9 @@
 #include <machine/param.h>
 #include <machine/vmparam.h>
 
-int vm_cachecall(message *m, int call, void *addr, dev_t dev, off_t dev_offset,
-	ino_t ino, off_t ino_offset, u32_t *flags, int blocksize)
+static int vm_cachecall(message *m, int call, void *addr, dev_t dev,
+	off_t dev_offset, ino_t ino, off_t ino_offset, u32_t *flags,
+	int blocksize)
 {
     if(blocksize % PAGE_SIZE)
     	panic("blocksize %d should be a multiple of pagesize %d\n",
diff --git a/minix/lib/libsys/vm_map_phys.c b/minix/lib/libsys/vm_map_phys.c
index 1635c0e6e..40b59f858 100644
--- a/minix/lib/libsys/vm_map_phys.c
+++ b/minix/lib/libsys/vm_map_phys.c
@@ -13,7 +13,7 @@ vm_map_phys(endpoint_t who, void *phaddr, size_t len)
 
 	memset(&m, 0, sizeof(m));
 	m.m_lsys_vm_map_phys.ep = who;
-	m.m_lsys_vm_map_phys.phaddr = phaddr;
+	m.m_lsys_vm_map_phys.phaddr = (phys_bytes)phaddr;
 	m.m_lsys_vm_map_phys.len = len;
 
 	r = _taskcall(VM_PROC_NR, VM_MAP_PHYS, &m);